This invention relates generally to spray suppression devices, such as mud flaps, adapted for use on wheeled vehicles such as trucks. More particularly, the invention relates to an integrally-formed spray suppression device having openings adapted to allow air and water to pass therethrough. Each opening has a cover thereover to deflect substantially all of the incident water without clogging with roadway debris it encounters.
The term “spray” in the present application includes spray, splash or both. Splash and spray produced by large trucks in wet weather generally creates poor visibility for trailing and passing drivers. The terms “splash and spray” are commonly used together to describe the adverse effects on visibility caused by vehicles traveling on wet roads. “Splash” consists of very large liquid droplets that hit the pavement. Occasionally, splash may strike adjacent vehicles' windshields if there is puddling or uneven wetting of the roadway surface in front of the truck (or other vehicle). This condition can obscure vision for a brief period. “Spray” consists of very small liquid droplets that remain airborne for a long time in the form of a fog cloud before falling to the ground. Spray is formed when three elements are present: (1) water, (2) a hard or smooth surface struck by the water, and (3) turbulent air flow to pick up and carry the water after it strikes the surface. The interaction of the three elements produces small droplets of water which remain airborn for a time, in the form of a “fog” cloud projecting from the surface which they struck last. Because the “fog” can linger as long as the cloud's water is replenished, spray can surprise and confuse a driver who is not able to orient himself and his vehicle because of the inability to see through the cloud of airborne water droplets. The cumulative consequences of splash and spray are primarily depositing dirt on surfaces critical to visibility—windshields and windows, mirrors, signs, and vehicle bodies—influencing what drivers can see and how well they can see. Visibility and driver vision issues related to splash and spray can also play a significant role in terms of pedestrian safety. Splash can be a problem for drivers of following vehicles attempting to pass (or driving in adjacent lanes) and oncoming vehicles, with the concern being a potential loss of control.
While conventional solid mud flaps, which have no through openings, are somewhat effective in deflecting water and roadway debris, they suffer from several disadvantages. First, the solid surface design of the conventional mud flap prevents air from passing through it, thereby increasing the drag created by the mud flap and decreasing fuel economy. Also, the lower portion of a solid mud flap may be displaced rearwardly when the vehicle is moving at high rates of speed, thereby reducing the amount of water and debris the mud flap deflects. Further, the conventional solid mud flap increases the temperature in the area of the tire of the vehicle because air is not permitted to flow through the mud flap. Increased temperature in the area of the tire increases the risk of tire failure. In addition, the solid design of the typical mud flap prevents any water or other roadway debris encountered by the mud flap from passing through the mud flap. As a result, a large proportion of the water and other roadway debris encountered by a conventional solid mud flap is projected off the sides of the mud flap and into the paths of other vehicles.
An example of the common prior art on heavy trucks to help reduce wheel spray is the traditional mud flap that is enhanced with surface materials ranging in nature from Astroturf® or grass-like material to grooved surface treatments. The basic intent of a grass-like substance is to absorb and dissipate the energy of the water spray, temporarily trapping water within its texture prior to draining it on to the road surface behind the tire(s). However, the grass-like spray suppressions can become clogged with mud, rocks, and other road debris.
Several modifications have been made to the conventional solid mud flap to address the disadvantages identified above. For example, non-grass options were being looked at to reduce/eliminate clogging of the flap. Further, mud flaps have been provided with openings to permit some air, water and other debris to pass through the mud flap. Typically, the openings are defined, at least in part, by rearwardly and downwardly extending louvers or flaps. For example, U.S. Pat. No. 3,350,114 to Salisbury describes a mud flap having a plurality of flexible flaps adapted to be opened by a stream of water and capable of deflecting said stream downwardly. Absent a stream of water, however, the flexible hinged flaps remain substantially closed over the aperture with which each is associated. As a result, the flexible flaps do little to reduce the drag created by the mud flap, the weight of the mud flap, the rearward displacement of the bottom of the mud flap at high speeds, or the increased temperature in the area of the tire.
Several patents describe mud flaps having openings defined by louvers. See, e.g. U.S. Pat. Nos. 3,088,751; 4,660,846; and 4,921,276. U.S. Pat. No. 5,366,247 to Fischer describes a vehicle splashguard having louvers adapted to deflect water and other debris downwardly rather than sidewardly or rearwardly into the path of following traffic. The louvers extend generally horizontally across substantially the entire width of the splashguard. Similarly, U.S. Pat. No. 5,564,750 to Bajorek et al. describes a mud flap having louvers that extend horizontally across substantially the entire width of the mud flap. In addition, the mud flap of Bajorek includes a vertical rib member midway between the ends of each louver to provide vertical support to the louvers.
U.S. Pat. No. 5,582,430 to Bauer, et al. describes a spray protection device having an inlet layer and a spacer layer which creates a void therebetween. EP 899,185 to Turpeinen, et al. discloses a method of forming openings and spray-guiding members in a splash panel to be affixed to the mudguard and/or the mud-flap of a vehicle or the like for collecting and guiding spray of surface water from the wheels.
The prior art spray suppression devices that utilize 3-dimensional protrusions (i.e. plastic grass, studs, etc.) or other materials with small holes (i.e. mesh netting, fabrics, etc.) are all easily clogged with mud, rocks, and road debris. Cleaning these devices can be difficult, time consuming, and expensive. Several examples of three dimensional thermoplastic spray suppression devices consisting of vanes, ribs, channels, perforations, holes, and injection molded surfaces exist in the prior art and have tried to solve this problem of clogging while still meeting minimum spray suppression requirements. Many of these devices have portions of their surface which are flat and devoid of spray suppression potential.
It would be desirable, therefore, if a mud flap could be provided which reduces the amount of splash and spray that is projected off the sides and tread portion of the wheels (including the tires). It would also be desirable if a mud flap could be provided which allows air to pass through its opening without clogging with mud, rocks, and road debris.
Further objectives and advantages of the present invention will become apparent from a careful reading of a detailed description provided hereinbelow, with appropriate reference to accompanying drawings.